Crack in the Soil Stack Near Basement Floor

Hi Everyone-

Wanted to make my first post something more positive, but I noticed a leak in the soil stack in the basement today. In the pictures below, you can see it is a small almost hairline crack. It is leaking slightly, mostly drops that come out at the top and roll down the side and collect at the bottom. The crack appears to extend to the floor, but I can't really tell because it wraps behind and I lose view.

Can I put Harvey's Soil-Seal on this or should I call a plumber? My fear with Soil Seal is that the crack extends below the floor surface, meaning I won't completely seal it and it will leak below. I would imagine if this can't be sealed that this is going to be a huge (expensive) job seeing it is at the very bottom of a cast iron soil stack!

That stack goes into an elbow or T below the slab----if the T or elbow and the lateral line are still sound---the slab needs to be opened---the old stack cut and removed from the hub on the fitting and replaced with PVC--

It goes all the way up through the attic and out of the roof. The picture below shows the top portion in the basement...you can see where the foundation ends and it goes into the first floor. Looks like someone already replaced the old cleanout.

yeah, i know.
but is it a 1 story, or 2 or 3 ? outside wall, interior wall ? how thick is the pipe, and the walls it runs through ? what does the stack on the roof look like ?

Sorry, I was trying to think of the best way to answer your question and I think I came up with the biggest "Duh" factor answer.

It's about a 4-6" diameter cast iron pipe. It's on the outside wall in the back, goes up two stories, through the attic, and out. From what I remember last time I was up in the attic, there is another PVC coupling in the attic, but it is the same diameter where the pipe exits. I'll snap a shot tomorrow.

Seriously Ugly. Replace it all from the wrongfully installed no-hub connector to PVC up. Those connectors are for joining CI to CI. Not CI to PVC. Keep the cleanout at 4 inches, why reduce to 3" ???

That looks like everything else that was done in the house...at least that one was not done by the "licensed contractor" who "flipped" the house!

I'm getting the feeling that this one is going to beyond the scope of a DIY....especially if I get down to the lateral under the cement and find other issues. Besides, it is a soil stack. If I do a lousy tape and mud job on drywall it's just annoying to look at in certain light. If I foul up the main soil stack...

I really appreciate everyone's feedback. I will update this thread after I get a plumber out... even though it won't be a DIY it will serve as info for anyone else in the same situation.